Input: psmouse - fix OOB access in Elantech protocol

The kernel only allocate 5 MT slots; check that transmitted slot ID
falls within the acceptable range.

Link: https://lore.kernel.org/r/ZFnEL91nrT789dbG@google.com
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Dmitry Torokhov 2023-05-11 12:08:37 -07:00
parent 20a99a291d
commit 7b63a88bb6
1 changed files with 5 additions and 4 deletions

View File

@ -674,10 +674,11 @@ static void process_packet_head_v4(struct psmouse *psmouse)
struct input_dev *dev = psmouse->dev;
struct elantech_data *etd = psmouse->private;
unsigned char *packet = psmouse->packet;
int id = ((packet[3] & 0xe0) >> 5) - 1;
int id;
int pres, traces;
if (id < 0)
id = ((packet[3] & 0xe0) >> 5) - 1;
if (id < 0 || id >= ETP_MAX_FINGERS)
return;
etd->mt[id].x = ((packet[1] & 0x0f) << 8) | packet[2];
@ -707,7 +708,7 @@ static void process_packet_motion_v4(struct psmouse *psmouse)
int id, sid;
id = ((packet[0] & 0xe0) >> 5) - 1;
if (id < 0)
if (id < 0 || id >= ETP_MAX_FINGERS)
return;
sid = ((packet[3] & 0xe0) >> 5) - 1;
@ -728,7 +729,7 @@ static void process_packet_motion_v4(struct psmouse *psmouse)
input_report_abs(dev, ABS_MT_POSITION_X, etd->mt[id].x);
input_report_abs(dev, ABS_MT_POSITION_Y, etd->mt[id].y);
if (sid >= 0) {
if (sid >= 0 && sid < ETP_MAX_FINGERS) {
etd->mt[sid].x += delta_x2 * weight;
etd->mt[sid].y -= delta_y2 * weight;
input_mt_slot(dev, sid);